Andrew Gilligan's former bosses at the BBC are preparing to blame him for the mistakes in the Iraq dossier story that led to the death of David Kelly.

At an internal investigation in the aftermath of the Hutton report, they will characterise him as a "rogue reporter" who "went off piste" during his infamous 6.07am broadcast on May 29 last year.

Furious at Lord Hutton's claim that editorial procedures were "defective", they will argue that Gilligan's notes were checked and a script agreed before he went on air last May, but that the reporter failed to stick to it.

Gilligan, who quit the BBC last Friday, is understood to be frustrated at being saddled with most of the blame. "If he was a rogue reporter, he would hardly have lasted four years at the BBC," a friend said.

He will not be part of the internal "process" - the BBC refuses to call it an investigation or an inquiry - which will seek to establish whether there were any systemic editorial failures in the run-up to broadcast and the aftermath.

Many at the BBC believe Lord Hutton's inquiry was defective in this regard, since he did not call the editor of the Today programme, Kevin Marsh, or the head of radio news, Stephen Mitchell. Marsh, Mitchell and others at the BBC are determined to show that they made all the necessary checks before the Gilligan story was broadcast. "Understandably, people like Kevin and Stephen want their day in court," said one BBC source.

Despite the claim that managers did not check Gilligan's personal organiser notes for a month, BBC sources say that Marsh did see a set of notes entered into the BBC's internal computer system on May 28. These notes were used to script the following day's 7.32am "two-way" (where a journalist responds to questions relating to his or her story), and did not contain the assertion that the government inserted the 45-minute claim into the Iraq dossier knowing it was wrong.

BBC sources say Gilligan should have had the 7.32am script in front of him when he made the 6.07am broadcast. "That's the convention," said one Today programme source. Another BBC source added: "There's this idea that the 6.07 wasn't scripted, but Andrew should have had the 7.32 script in front of him, and should not have deviated from it."

Marsh and Mitchell are understood to fear losing their jobs at the end of the BBC inquiry. Part of the desire to blame Gilligan can be attributed to this concern. "There is something of a dog-eat-dog atmosphere," one source said.

But more senior figures at the BBC believe that neither Marsh nor Mitchell will be forced out. "Kevin clearly performed the editorial checks that would be expected of him. But you can't legislate for a rogue reporter who goes off piste," one said.

There is a feeling at the BBC that the corporation backed itself into a corner at the Hutton inquiry by publicly throwing its weight behind Gilligan. Now, the BBC is struggling to explain which parts of Lord Hutton's report it accepts. "At some point, we are going to have to say that we don't agree with all this shit," one of the key players said.

Gilligan has decided not to make any further public statements on the issue for the time being. He is believed to be resigned to being blamed by his former bosses.

A friend said: "It would be really, really unfair to Andrew, on top of all the other unfair things that have happened. Kevin Marsh isn't a bad man, but obviously they are all trying to protect their careers. But the essential problem was the failure to recognise what sort of story this was. That was an editorial failure."